A group
called The Secret Organisation of al-Qaida in Europe today said it carried out the series of
blasts in London in retaliation for Britain's involvement in Iraq and Afghanistan.

The group's statement appeared on a website
popular with Islamic militants, according to Elaph, a
secular Arabic-language news website, and Der Spiegel
magazine in Berlin,
which both published the text on their sites.

The statement, which also threatened attacks
against Italy and Denmark, said:
"Rejoice, Islamic nation. Rejoice, Arab world. The time has come for
vengeance against the Zionist crusader government of Britain
in response to the massacres Britain
committed in Iraq and Afghanistan."

The authenticity of the message could not be
immediately confirmed, but al-Qaida in Europe also
claimed responsibility for the last major terror attack in Europe: a string of
bombs that hit commuter trains in Madrid,
Spain, in March
2004 that killed 191 people.

The group appeared to boast that it had spent
some time planning the attack.

"We have repeatedly warned the British
government and people. We have fulfilled our promise and carried out our
blessed military raid in Britain after our Mujahideen
exerted strenuous efforts over a long period of time to ensure the success of
the raid," the website posting read.

Michael Clarke, director of the Centre for Defence Studies at King's College, London, said six bombs would mean at least 24
people were involved in planting them in a targeted operation.

The fact that London had been hit when the resources of the
security forces were focused on the G8 summit at Gleneagles showed thoughtful
preparation by terrorists.

"It will have been quite a big plot and
months in the planning," said Prof Clarke, who declined to speculate who
was behind the attacks at this stage.

The danger of further explosions during the day
could not be ruled out, he added. "The way to really bring a city to a
halt is to explode some more bombs when the rescue services are running
around."

Last month, Ken Jones, the chairman of the
Association of Chief Police Officers' terrorism committee and chief constable
of Sussex, said Britain would
remain a prime target for terrorists. "There is an inevitable targeting of
the United Kingdom and UK interests abroad," Mr
Jones told a conference on terrorism organised by the
Royal United Services Institute in London.
"The threat will endure for the foreseeable future."